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Scanning electron microscope as a commonly used microscopic analysis tools, can be observed on all types of metal fracture, fracture type determination, morphology analysis, failure analysis and other research.   What is a metal fracture?   When a metal is broken by an external force, two matching sections are left at the fracture site, which is called a "fracture". The shape and appearance of this fracture contains a lot of important information about the fracture process.   By observing and studying the morphology of the fracture, we can analyze the cause, nature, mode, mechanism, etc., and also understand the details of the stress condition and crack expansion rate at the time of fracture. Like a "scene", the fracture retains the whole process of fracture occurrence. Therefore, for the study of metal fracture problems, observation and analysis of fracture is a very important step and means. Scanning electron microscope has the advantages of large depth of field and high resolution, and has been widely used in the field of fracture analysis.   Application of Scanning Electron Microscope in Metal Fracture Analysis   There are various forms of failure of metal fracture. Categorized by the degree of deformation before fracture, they can be divided into brittle fracture, ductile fracture, and mixed brittle and ductile fracture. Different fracture forms will have characteristic microscopic morphology, which can be characterized by SEM to help researchers to quickly perform fracture analysis.   Ductile Fracture   Ductile fracture is a fracture that occurs after a large amount of deformation of a member, which is mainly characterized by significant macroplastic deformation. The macroscopic morphology is a cup-and-cone fracture or a pure shear fracture, and the fracture surface is fibrous and consists of tough nests. As shown in Figure 1, microscopically its fracture is characterized by: the fracture surface consists of a number of tiny wineglass-shaped microporous pits, usually referred to as tough fossa. Toughness fossa is the trace left on the fracture surface after plastic deformation of the material in the range of micro-region generated by the micro-void, through the nucleation/growth/aggregation, and finally interconnected to lead to fracture.     Fig. 1 Metal ductile fracture fracture/10kV/Inlens   Brittle Fracture   Brittle fracture is the fracture of a member without significant deformation. There is little plastic deformation of the material at the time of fracture. While macroscopically it is crystalline, microscopically it includes fracture along the crystal, disintegration fracture or quasi-disintegration fracture. As shown in Fig. 2, a mixed brittle-ductile fracture fracture of the metal, in the ductile fracture region, a distinctive toughness nest feature can be observed. In the brittle fracture region, it belongs to along-crystalline brittle fracture, which refers to the fract...

5A molecular sieve is a kind of calcium-type aluminosilicate with cubic lattice structure, also known as CaA-type zeolite. 5A molecular sieve has developed pore structure and excellent selective adsorption, which is widely used in the separation of n-isomerized alkanes, the separation of oxygen and nitrogen, as well as natural gas, ammonia decomposition gas, and the drying of other industrial gases and liquids. 5A molecular sieve has an effective pore size of 0.5 nm, and the determination of the pore distribution is generally characterized by gas adsorption using a physical adsorption instrument. The effective pore size of 5A molecular sieve is about 0.5 nm, and its pore size distribution is generally characterized by gas adsorption using physical adsorption instrument. The specific surface and pore size distribution of 5A molecular sieves were characterized by CIQTEK EASY-V series specific surface and pore size analyzers. Before testing, the samples were degassed by heating under vacuum at 300℃ for 6 hours. As shown in Fig. 1, the specific surface area of the sample was calculated as 776.53 m2/g by the multi-point BET equation, and then the microporous area of the sample was obtained as 672.04 m2/g, the external surface area as 104.49 m2/g, and the volume of the microporous as 0.254 cm3/g by t-plot method, which showed that the microporous area of this molecular sieve accounted for about 86.5%. In addition, the analysis of the N2 adsorption-desorption isotherm plot of this 5A molecular sieve (Fig. 2, left) reveals that the adsorption isotherm shows that the adsorption amount increases sharply with the increase of the relative pressure when the relative pressure is small, and the filling of micropores occurs, and the curve is relatively flat after reaching a certain value, which suggests that the sample is rich in micropores. The microporous pore size distribution calculation using the SF model (Fig. 2, right panel) yielded a concentrated microporous pore size distribution at 0.48 nm, which is consistent with the pore size of 5A molecular sieves.   Fig. 1 Specific surface area test results (left) and t-Plot results (right) of 5A molecular sieve   Fig. 2 N2-sorption and desorption isotherms (left) and SF-pore size distribution plots (right) of 5A molecular sieve samples      CIQTEK Automatic BET Surface Area & Porosimetry Analyzer | EASY-V 3440 EASY-V 3440 is the BET specific surface area and pore size analysis instrument developed independently by CIQTEK, using the static volumetric method.   ▪  Specific surface area testing, range 0.0005 (m2/g) and above. ▪  Pore size analysis: 0.35 nm-2 nm (micropore), micropore size distribution analysis; 2 nm-500 nm (mesopore or macropore). ▪  Four analysis stations, simultaneous testing of 4 samples. ▪  Equipped with the molecular pump.

Zeolite imidazolium skeleton (ZIFs) materials as a subclass of metal-organic skeletons (MOFs), ZIFs materials combine the high stability of inorganic zeolites and the high specific surface area, high porosity and tunable pore size of MOFs materials, which can be applied to efficient catalytic and separation processes, so ZIFs and their derivatives have good potential for use in catalysis, adsorption and separation, electrochemistry, biosensor and biomedicine and other fields with good application prospects. The following is a case study of the characterization of ZIF molecular sieves using CIQTEK EASY-V series specific surface and pore size analyzer. As shown in Fig. 3 left, the specific surface area of this ZIF molecular sieve is 857.63 m2/g. The material has a large specific surface area which is favorable for the diffusion of reactive substances. From the N2-adsorption and desorption isotherms (Fig. 3, right), it can be seen that there is a sharp increase in adsorption in the low partial pressure region (P/P0 < 0.1), which is attributed to the filling of micropores, indicating that there is a certain amount of microporous structure in the material, and there is a hysteresis loop within the range of P/P0 of about 0.40 to 0.99, which suggests that there is an abundance of mesoporous structure in this ZIF molecular sieve. The SF-pore size distribution graph (Fig. 4, left) shows that the most available pore size of this sample is 0.56 nm. The total pore volume of this ZIF molecular sieve is 0.97 cm3/g, and the microporous volume is 0.64 cm3/g, with 66% of micropores, and the microporous structure can significantly increase the specific surface area of the sample, but the molecular sieve will limit the catalytic activity under certain conditions due to the smaller pore size. However, under certain conditions, the smaller pore size will limit the diffusion rate of the catalytic reaction, which makes the performance of molecular sieve catalyst limited, however, the mesoporous structure can obviously make up for this defect of the microporous structure, so the structure of the combination of microporous-mesoporous can effectively solve the problem of the limitation of the mass transfer capacity of the traditional molecular sieve with a single pore.   Fig. 1 Specific surface area test results (left) and N2-sorption and desorption isotherms (right) for ZIF molecular sieves Fig. 2 SF-pore size distribution (left) and NLDFT-pore size distribution (right) of ZIF molecular sieve

The characterization of copper foil morphology by scanning electron microscopy can help researchers and developers to optimize and improve the preparation process and performance of copper foils to further meet the existing and future quality requirements of high-performance lithium-ion batteries. Wide Range of Copper Applications Copper metal is widely used in lithium-ion batteries and printed circuit boards because of its ductility, high conductivity, ease of processing and low price. Depending on the production process, copper foil can be categorized into calendered copper foil and electrolytic copper foil. Calendered copper foil is made of copper blocks rolled repeatedly, with high purity, low roughness and high mechanical properties, but at a higher cost. Electrolytic copper foil, on the other hand, has the advantage of low cost and is the mainstream copper foil product in the market at present. The specific process of electrolytic copper foil is (1) dissolving copper: dissolve raw copper to form sulfuric acid-copper sulfate electrolyte, and remove impurities through multiple filtration to improve the purity of the electrolyte. (2) Raw foil preparation: usually polished pure titanium rolls as the cathode, through electrodeposition of copper ions in the electrolyte is reduced to the surface of the cathode to form a certain thickness of copper layer. (3) Surface treatment: the raw foil is peeled off from the cathode roll, and then after post-treatment, the finished electrolytic copper foil can be obtained. Figure 1 Electrolytic Copper Foil Production Process Copper Metal in Lithium-ion Batteries Lithium-ion batteries are mainly composed of active materials (cathode material, anode material), diaphragm, electrolyte and conductive collector. Positive potential is high, copper is easy to be oxidized at higher potentials, so copper foil is often used as the anode collector of lithium-ion batteries. The tensile strength, elongation and other properties of copper foil directly affect the performance of lithium-ion batteries. At present, lithium-ion batteries are mainly developed towards the trend of "light and thin", so the performance of electrolytic copper foil also puts forward higher requirements such as ultra-thin, high tensile strength and high elongation. How to effectively improve the electrolytic copper foil process to enhance the mechanical properties of copper foil is the main research direction of copper foil in the future. Suitable additive formulation in the foil making process is the most effective means to regulate the performance of electrolytic copper foil, and qualitative and quantitative research on the effect of additives on the surface morphology and physical properties of electrolytic copper foil has been a research hotspot for scholars at home and abroad. In materials science, the microstructure determines its mechanical properties, and the use of scanning electron microscopy to characterize the changes in the surface micro-m...

Environmental pollution is one of the global crises and is affecting the quality of living and health of the entire population. A new class of harmful substances, the environmentally persistent free radicals (EPFRs). These pollutants are pervasive and can be found in air, water, and soil. The EPFRs can be recognized as biohazard since it can produce reactive oxide species (ROS), which causes cell and tissue damages and ultimately cancer. To mitigate and eventually find a solution to this problem, tracing the origin of such pollutants is needed. Electron paramagnetic resonance (EPR) spectroscopy is a powerful tool and can be used for such tasks.   What are EPFRs   The conventionally recognized free radicals are often transient with a short lifetime. On the contrary, EPFRs can be stable in the environment for tens of minutes to tens of days without being oxidized or quenched. The commonly found EPFRs include, cyclopentadienyl, semiquinone, phenoxy, and other radicals.     Common EPFRs     Where do EPFRs come from?   EPFRs are found in a wide range of environmental media, such as atmospheric particulate matter (e.g. PM 2.5), factory emissions, tobacco, petroleum coke, wood and plastic, coal combustion particulates, soluble fractions in water bodies, and organically contaminated soils, etc. EPFRs have a wide range of transport pathways in environmental media and can be transported through vertical ascent, horizontal transport, vertical deposition to water bodies, vertical deposition to land, and landward migration of water bodies. In the process of migration, new reactive radicals may be generated, which directly affects the environment and are precursors to other pollutants.   Formation and Multimediated Transfer of EPFRs (Environmental Pollution 248 (2019) 320-331)     Application of EPR Technique for the Detection of EPFRs   EPR spectroscopy is extremely sensitive to unpaired electrons, and a directly measurement of signals from these radicals make it an ideal method for monitoring the presence of EPFRs in different samples.  . For the detection of EPFRs, EPR (ESR) spectroscopy provides information in both spatial and temporal dimensions. By measuring and analyzing the continuous-wave EPR spectra of samples, the researchers are able to not only verifying the presence of radicals but also obtain g-values and hyperfine coupling constants of electrons, which can be used for inferring electronic structure of measured molecules. The temporal resolution refers to the half-life of EPFRs, which can also be obtained from monitoring their EPR signals over time.     Application of EPR Technology in Detecting EPFRs in the Soil Environment   Petroleum processing, storage, transportation, and possible leakage from storage tanks are all susceptible to soil contamination. Although thermal treatment techniques can be used to remediate soils contaminated by various volatile, semi-volati...